ipsec_act_ovhd
ap->ipa_ovhd = ipsec_act_ovhd(&ap->ipa_act);
overhead = ipsec_act_ovhd(&a[i]);
extern int32_t ipsec_act_ovhd(const ipsec_act_t *act);
ipsec_act_ovhd(&pol->ipsp_act->ipa_act));
ipsec_ovhd = ipsec_act_ovhd(&pol->ipsp_act->ipa_act);
ipsec_act_ovhd(&pol->ipsp_act->ipa_act));